zmq: accept unix domain socket address for notifier

src/init.cpp

@@ -1301,30 +1301,33 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         }
     }
 
-    for (const std::string port_option : {
-        "-i2psam",
-        "-onion",
-        "-proxy",
-        "-rpcbind",
-        "-torcontrol",
-        "-whitebind",
-        "-zmqpubhashblock",
-        "-zmqpubhashtx",
-        "-zmqpubrawblock",
-        "-zmqpubrawtx",
-        "-zmqpubsequence",
+    for (const auto &port_option : std::vector<std::pair<std::string, bool>>{
+        // arg name            UNIX socket support
+        {"-i2psam",                 false},
+        {"-onion",                  true},
+        {"-proxy",                  true},
+        {"-rpcbind",                false},
+        {"-torcontrol",             false},
+        {"-whitebind",              false},
+        {"-zmqpubhashblock",        true},
+        {"-zmqpubhashtx",           true},
+        {"-zmqpubrawblock",         true},
+        {"-zmqpubrawtx",            true},
+        {"-zmqpubsequence",         true}
     }) {
-        for (const std::string& socket_addr : args.GetArgs(port_option)) {
+        const std::string arg{port_option.first};
+        const bool unix{port_option.second};
+        for (const std::string& socket_addr : args.GetArgs(arg)) {
             std::string host_out;
             uint16_t port_out{0};
             if (!SplitHostPort(socket_addr, port_out, host_out)) {
 #if HAVE_SOCKADDR_UN
-                // Allow unix domain sockets for -proxy and -onion e.g. unix:/some/file/path
-                if ((port_option != "-proxy" && port_option != "-onion") || socket_addr.find(ADDR_PREFIX_UNIX) != 0) {
-                    return InitError(InvalidPortErrMsg(port_option, socket_addr));
+                // Allow unix domain sockets for some options e.g. unix:/some/file/path
+                if (!unix || socket_addr.find(ADDR_PREFIX_UNIX) != 0) {
+                    return InitError(InvalidPortErrMsg(arg, socket_addr));
                 }
 #else
-                return InitError(InvalidPortErrMsg(port_option, socket_addr));
+                return InitError(InvalidPortErrMsg(arg, socket_addr));
 #endif
             }
         }

src/zmq/zmqnotificationinterface.cpp

@@ -8,6 +8,7 @@
 #include <kernel/chain.h>
 #include <kernel/mempool_entry.h>
 #include <logging.h>
+#include <netbase.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
 #include <validationinterface.h>
@@ -57,7 +58,12 @@ std::unique_ptr<CZMQNotificationInterface> CZMQNotificationInterface::Create(std
     {
         std::string arg("-zmq" + entry.first);
         const auto& factory = entry.second;
-        for (const std::string& address : gArgs.GetArgs(arg)) {
+        for (std::string& address : gArgs.GetArgs(arg)) {
+            // libzmq uses prefix "ipc://" for UNIX domain sockets
+            if (address.substr(0, ADDR_PREFIX_UNIX.length()) == ADDR_PREFIX_UNIX) {
+                address.replace(0, ADDR_PREFIX_UNIX.length(), ADDR_PREFIX_IPC);
+            }
+
             std::unique_ptr<CZMQAbstractNotifier> notifier = factory();
             notifier->SetType(entry.first);
             notifier->SetAddress(address);

src/zmq/zmqutil.h

@@ -9,4 +9,7 @@
 
 void zmqError(const std::string& str);
 
+/** Prefix for unix domain socket addresses (which are local filesystem paths) */
+const std::string ADDR_PREFIX_IPC = "ipc://"; // used by libzmq, example "ipc:///root/path/to/file"
+
 #endif // BITCOIN_ZMQ_ZMQUTIL_H